linux-kernel - Re: kvm: WARNING In kvm_apic_accept

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Message-ID: <04a86494-a032-83d9-b9f2-abd4e0c57f08@redhat.com>
Date:   Wed, 15 Feb 2017 10:26:34 +0100
From:   David Hildenbrand <david@...hat.com>
To:     Dmitry Vyukov <dvyukov@...gle.com>,
        Paolo Bonzini <pbonzini@...hat.com>
Cc:     Radim Krčmář <rkrcmar@...hat.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Ingo Molnar <mingo@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        "x86@...nel.org" <x86@...nel.org>, KVM list <kvm@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        Steve Rutherford <srutherford@...gle.com>,
        syzkaller <syzkaller@...glegroups.com>
Subject: Re: kvm: WARNING In kvm_apic_accept_events


>>> From: David Hildenbrand <david@...hat.com>
>>> Date: Mon, 23 Jan 2017 16:42:23 +0100
>>> Subject: [PATCH] KVM: x86: fix illegal MP_STATE when in/entering SMM
>>>
>>> If we already entered/are about to enter SMM, don't allow
>>> switching to INIT/SIPI_RECEIVED, otherwise the next call to
>>> kvm_apic_accept_events() will report a warning.
>>>
>>> Fixes: cd7764fe9f73 ("KVM: x86: latch INITs while in system management mode")
>>> Reported-by: Dmitry Vyukov <dvyukov@...gle.com>
>>> Signed-off-by: David Hildenbrand <david@...hat.com>
>>> ---
>>>  arch/x86/kvm/x86.c | 6 ++++++
>>>  1 file changed, 6 insertions(+)
>>>
>>> diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c
>>> index 57d8a85..06ffc91 100644
>>> --- a/arch/x86/kvm/x86.c
>>> +++ b/arch/x86/kvm/x86.c
>>> @@ -7247,6 +7247,12 @@ int kvm_arch_vcpu_ioctl_set_mpstate(struct kvm_vcpu *vcpu,
>>>           mp_state->mp_state != KVM_MP_STATE_RUNNABLE)
>>>               return -EINVAL;
>>>
>>> +     /* INITs are latched while in SMM */
>>> +     if ((is_smm(vcpu) || vcpu->arch.smi_pending) &&
>>> +         (mp_state->mp_state == KVM_MP_STATE_SIPI_RECEIVED ||
>>> +          mp_state->mp_state == KVM_MP_STATE_INIT_RECEIVED))
>>> +             return -EINVAL;
>>> +
>>>       if (mp_state->mp_state == KVM_MP_STATE_SIPI_RECEIVED) {
>>>               vcpu->arch.mp_state = KVM_MP_STATE_INIT_RECEIVED;
>>>               set_bit(KVM_APIC_SIPI, &vcpu->arch.apic->pending_events);
>>>
>>
>> Looks good, thanks for analyzing it.  I'll try making a minimal testcase...
> 
> 
> Any progress with this? Should we commit this as is?
> 

Paolo, should I resend as a proper notcopieddiff mail?

-- 
Thanks,

David